Researchers reported that moderate consumption of caffeinated beverages—about two to three cups of coffee or one to two cups of tea per day—was associated with a roughly 15–20% lower risk of developing dementia and with smaller, measurable slowing of cognitive decline.
The finding comes from a prospective analysis of 131,821 participants drawn from the Nurses’ Health Study and the Health Professionals Follow-Up Study, with repeated diet and health assessments over up to four decades; during follow-up more than 11,000 participants were documented to have developed dementia.
